365 Days of Slow Cooking's Yummy Ravioli

We had Yummy Ravioli from 365 Days of Slow Cooking cookbook.  This was an easy crockpot recipe, that my family of course loved.  Aaron and I gave it an 8, and the boys gave it a perfect 10.  The calories per serving, and we had 6 servings, were 513.  This is how I made it.

1/2 lb hamburger
1/2 medium onion
2 garlic cloves, minced
Italian seasonings, to taste
salt and pepper, to taste
3 c marinara sauce
1/2 c beef broth
20 oz cheese filled ravioli
8 oz mozzarella cheese, sliced
1/2 c parmesan cheese, grated

Cook meat, seasonings, onion and garlic together in a skillet.  Drain off grease, then add in the marinara sauce, beef broth, and a little water.  Simmer for 3-5 minutes.
Pour one third of the sauce in the slow cooker, then add in half of the ravioli, top with half of the cheeses, then repeat process, ending with the last 1/3 of the sauce.  cook on low for 5-6 hours (mine should've cooked less time), and serve.